Testing device for determining the condition of cam contours



p 18, 1955 T. J. GARRISON 2,763,066

TESTING DEVICE FOR DETERMINING THE CONDITION OF CAM CONTOURS Filed April '7, 1955 2 Sheets-Sheet l .Tbomas Jlarrz'son Q INVENTOR. BY

Sept. 18, 1956 T. J. GARRISON 2,763,066

TESTING DEVICE FOR DETERMINING THE CONDITION OF CAM CONTOURS Filed April '7, 1955 2 Sheets-Sheet 2 fiend.

INVENTOR Thomas J arrison rnsrnvo DEVICE FOR DETERMINING THE CONDITION OF CAM CONTOURS Thomas J. Garrison, Los Angeles, Calif.

Application April 7, 1955, Serial No. 499,888

6 Claims. (Cl. 33174) This invention relates to a testing device for ascertaining the condition of the contours of the cams on tengine cam-shafts, and has as its primary object the provision of a means whereby defects in the contoured surfaces of the cams of the camshaft of an engine may be indicated while the shaft is installed in operative condition and whereby removal of the shaft from its mounting for such purpose is rendered unnecessary.

As is well known, the operation of the internal combustion engine employed in motor vehicles involves the employment of a cam-shaft fitted with a series of cams which impel push-rods which in turn operate rockerarms that actuate spring seated valves controlling the engine intake and exhaust, the cams serving to time the operation of the valves. Manifestly any deformation of the cams, such as worn or pitted cam contours, is reflected in erratic operation of the valves with consequent irregularity of engine operation. There being other factors which interfere with smooth engine performance, such as improper timing of ignition and incorrect carburetion of the fuel delivered to the engine,

it is common practice, in tuning the motor to endeavor to correct faulty operation by first making ignition timer and carburetor adjustments and replacements without regard to the cam-shaft since the latter is not readily accessible and ordinarily involves considerable time and costs in effecting its removal and replacement.

The present invention is designed to enable quick determination of the condition of the several cams on the cam-shaft Without interfering with its mounting and whereby in event faulty operation of the engine is due to a defective cam or cams such may be readily ascertained and demonstrated; the invention contemplating the employment of an attachment to the push-rod together with an indicator actuated by combined movement of the push-rod and rotation of the cam shaft of an ignition timer or distributor whereby movement of the push-rod will be translated to the delineator so that on observing the latter during the operation, irregularity of movement of the push-rod and consequent erratic operation of the valve controlled thereby can be readily detected.

A further object is to provide a testing device for the purpose above set forth as well as for similar uses, which is simple in construction, which may be readily applied, and which is effective in its operation.

With the foregoing objects in view together with such other objects and advantages as may subsequently appear, the invention resides in the parts and in the com-' bination, construction and arrangement of parts hereinafter described and claimed, and as illustrated by way of example in the accompanying drawing in which:

Fig. l is a diagram in section and elevation illustrating the testing device as applied:

Fig. 2 is a detail in plan and horizontal section taken on the line 2-2 of Fig. 1:

Fig. 3 is a plan view as seen on the line 3-3 of Fig. 1:

Fig. 4 is an enlarged vertical section taken on the line Fig. 6 is a detail in cross section taken on the line 66 of Fig. 4: and

Fig. 7 is an enlarged detail in longitudinal section taken on the line 7 7 of Fig. 4.

Referring to the drawings more specifically A indicates the cam-shaft of an internal combustion engine, B designates a cam thereon and C denotes an upstanding push-rod seated on the cam B the upper end of which engages one end of a rocker arm D pivoted at E, the other end of which abuts the upper end of the stern F of a valve A spring H bears between a cap I and a cylinder head J and normally closes the valve G.

In carrying out the invention, use is made of the rotary shaft J of the ignition timer or distributor K, which shaft rotates in unison with the cam shaft A through the usual driving connections not shown.

The shaft J is utilized as a means for actuating in part a cam contour indicator L which embodies a revoluble horizontally extending disk 9 fixed on the upper end of a shaft 10 journalled on and extending through a baseplate 11 and fitted at its lower end with a chuck 12 whereby the shaft 10 can be detachably engaged with the upper end of a distributor shaft J to rotate with the latter. The disk 2 carries on its upper face a graphsheet 14 bearining a central delineation 15 complementary with the contour of the cam B, it being contemplated to provide a series of the sheets 14 bearing various delineations 15' according to various sizes and shapes of cams B employed in the various makes of motors in order to adapt the attachment for use in connection with the various motors. As a means for fastening the sheet 14 on the disk 9 upstanding pins a are mounted on the upper face of the disk 14 for detachable engagement with notches b in the perimeter of the disk 14, as particularly shown in Fig. 3.

Means are provided for holding the base plate 11 against turning on rotation of the shaft 10, which is here shown as comprising a tie-rod 16 one end of which is connected by a ball and socket joint 17 to a stem 18 fixed. on the plate 11 and the other end of which tie-rod is fitted with a clasp 19 for clamping engagement with a suitable projection M on the block of the engine to which the attachment is to be applied.

The base plate 11 is fitted with an upstanding flange 20 which affords a rigid support for a horizontally extending tubular housing 21 embodying an inner end portion 0 which projects through the flange 2i? and has an externally threaded outer end d engaged by an internally threaded intermediate housing section e. A shoulder f on the end portion 0 abuts the inner face of the flange 20 while the inner end of the section 0 abuts the outer face of the flange 20 so as to tightly fasten the housing 21 in place on the flange 20. The outer end of the housing section 2 is formed with internal threads g which engage a threaded nipple h on a cap i formed with a sleeve j which telescopes the outer end portion of the section e.

Extending into and through the nipple h is a tube 22 having a flange k on its inner end abutting the inner end of the nipple h and projecting into the outer end of the tube 22 is a flexible tube 23 which is aflixed to the tube 22 by set screw I mounted in a collar m encompassing the outer end portion of the tube 22 and abutting the cap 1'. Extending longitudinally through the tube 23 is a wire 24 the inner end of which is afflxed to a reciprocal shaft 25 slidably'supporte'd by and extending lengthwise through the end portion 0 of the housing 21, the shaft 25 being held against turning relative to the housing 21 by a key n carried by the end portion c and extending transversely of a flat face formed on the shaft 25, as particularly shown in Fig. 6.

interposed between the flange k on the tube 22 and a shoulder p the inner portion of the shaft 25 is a coiled expansion spring 26 which exerts a longitudinal thrust on the shaft 25 tending to normally advance the latter outwardly relative to the housing 21 and to exert a pull on the wire 24.

The outer end of the shaft 25 is formed with a head 27 on which is mounted for vertical adjustment a tubular element 28 carrying a stylus 29 which projects downwardly from the head 27 and terminates adjacent to or in Sliding contact with the sheet 14 and is normally presented to the delineation on the latter. A set screw 30 is mounted on the head 27 for engagement with the element 28 to securely hold the latter in its adjusted position.

The flexible tube 23 and the wire 24 therein lead to an actuator N which is designed for attachment to the push-rod C in such manner that longitudinal reciprocal movement of the rod will effect corresponding movement to the wire 24 and shaft 25 and thereby be translated into movement of the stylus 29 transversely of the disk 9 and sheet 14 thereon. The actuator N embodies a cylinder 31 fitted with a clamp P by means of which it may be rigidly attached to the push rod C and positioned in longitudinal parallel relation thereto. The clamp P embodies a block 32 which slidably encompasses the cylinder 31 and is thereby adjustable to various positions along the length of the cylinder. A set screw 33 carried by the block 32 is engageable with the cylinder 31 to securely hold the block 32 in its adjusted positions.

The block 32 is formed on one side margin thereof with a vertical slot 34 having a width slightly exceeding the diameter of the push-rod C and thus adapted to be positioned astride the latter. As a means for clamping the rod C in the slot 34 a slidebar 35 is mounted for longitudinal movement on the block 32, which bar slidably extends transversely through the block with its ends protruding from opposite sides thereof. One side of one portion end of the slide bar 35 intersects the slot 34 and is formed with a V-notch q presented toward the slot 34 and adapted to be positioned astride the push-rod C while the other end portion of the slide-bar is formed with threads on which is screwed a knurled nut 36 which bears against the adjacent side of the block 31 and is operable on rotation thereof to advance or retract the push-rod 35 which is held against rotation by means of a screw r threaded in the block 31 and extended into a longitudinal slot s in the slide bar. To effect clamping engagement of push-rod C with the block 32, the slide bar 35 is initially disposed in an advanced position, on retracting the nut 36 thereon, such that the notch q can be positioned astride the push-rod as indicated in dotted lines in Fig. 2. On this being accomplished, the slide bar 35 is retracted by advancing the nut 36 thereon so as to draw the push-rod C and block 32 toward each other until the push-rod is firmly seated in the slot 34. When the block 32 is thus attached to the push rod C, the cylinder 31 will be carried on the push-rod to move longi tudinally in unison therewith.

Mounted in the cylinder 31 is a reciprocal piston 37 which projects below the lower end of the cylinder and is fitted on its lower end with an axial stem 38 having a threaded end portion t screwed into the piston for longitudinal adjustment relative to the latter, the stem being equipped with a knurled finger hold 1: whereby it may be readily grasped and rotated.

The stem is formed with a pointed lower end v for seated engagement on a horizontal wall portion of the cylinder head or engine block adjacent the push-rod C.

The piston 37 is fitted with a stem 39 which extends through the upper end wall w of the cylinder 31 and has a laterally extending projection 40 fixed on its upper end portion to which is rigidly attached a tube 41 which extends through the projection 40 parallel with the stem 39. The upper end of the tube 41 is aidxed to and extends in continuation of the flexible tube 23. A lateral projection 42 is fixed on the upper end of the cylinder 31 and extends in parallel relation to the projection 40. A stem 43 fastened to the projection 42 slidably extends into the lower end of the tube 41 and has its outer end affixed to the wire 24. A coiled expansion spring 44 encompasses the piston stem 39 within the cylinder 31 and bears between the piston 37 and the cylinder end wall w so as to exert opposing thrusts on the piston 37 and cylinder 31 whereby the piston 37 is maintained in an advanced position relative to the cylinder so that when the latter is applied to the push-rod C with the stem 38 abutting the wall] the stem 38 will be held in such seated position during reciprocal movement of the cylinder 31 with the pushrod. The thrust thus exerted on the piston 37 by the spring 44 is translated through the piston stem 39 and projection 40 to the tube 41 and flexible tube 23 so as to hold the latter against longitudinal movement relative to the wire 24 and whereby the wire 24 can reciprocate within the tube 23 when moved with the cylinder 31.

In the application and operation of the invention, the indicator L is attached to the distributor shaft I by means of the chuck 12, and the base 11 with its superstructure including the housing 21 is fastened against rotation by means of the tie rod 16 and clasp 19. The actuator N is clamped on a push-rod as before described with the projections 40 and 42 spaced apart and with the stem 38 seated on the engine wall I and with the spring 44 under tension. A sheet 14 bearing a delineator 15 corresponding to the contour of the cam B to be tested is afiixed to the disk 9, and positioned so that the stylus 29 will be seated or directed toward the portion of the delineation 15 corresponding to the portion of the cam B engaging the push-rod, such as intermediate the low or dwell portion of the cam wherein the valve G is closed. On rotating the cam shaft A, the cam B will actuate the pushrod C movement of which will be translated to the stylus 29 to advance and retract the latter over the then revolving sheet 14 which moves in unison with the cam B.

Normally the stylus will traverse the cam delineation 15 in register therewith but in event of any irregularity in the cam contour such will be reflected by erratic movement of the stylus relative to the delineation 15 thus indicating such irregularity to an observer. In this fashion the several cams B on a cam shaft A may be tested and their condition readily determined.

I claim:

1. In a cam testing mechanism for indicating the condition of the contour of a cam on an engine cam shaft while in operative position, a disk bearing the delineation of a cam to be tested, a rotary shaft carrying said disk, means on said shaft for detachably engaging a distributor shaft, a longitudinally reciprocal shaft having an outer end portion projecting over said disk, a housing mounted on said shaft, a stylus carried on the outer end portion of said reciprocal shaft designating said cam delineation, a flexible tubular shaft connected to said housing, a wire extending through said tubular shaft connected to said reciprocal shaft, and means controlled by the cam being tested connected to said wire for moving said reciprocal shaft to cause said stylus to traverse said delineation during rotation of said disk and indicate to an observer by irregular movement of said stylus relative to the delineation any irregularity of the contour of the cam being tested.

2. The structure called for in claim 1 in which said cam controlled means comprises a reciprocal member to which said wire is attached and a clamp on said member engageable with the push rod actuated by the cam being tested.

3. In a cam testing mechanism for indicating the condition of the contours of the cams on cam shafts of engines which latter embody push-rods actuated by the cams and include a distributor shaft rotated in unison With the cam shaft, a rotary disk bearing a cam delineation corresponding to the contour of the cam being tested, a shaft on which said disk is axially mounted, means for detachably connecting said shaft to said distributor shaft to rotate in unison therewith, a stylus arranged to indicate said delineation, a reciprocal shaft on which said stylus is carried, a mounting for said reciprocal shaft, a wire having one end thereof attached to said reciprocal shaft, a reciprocal member to which the other end of said wire is attached, a clamp on said member engageable with the push rod actuated by the cam being tested, and a tubular shaft encompassing said Wire having one end fixed to the mounting of said reciprocal shaft, and a stationary member relative to which said reciprocal member is movable to which the other end of said tubular shaft is afiixed.

4. The structure called for in claim 3 together with an expansion spring in said reciprocal shaft mounting exerting a longitudinal forward thrust on said reciprocal shaft.

5. In a cam testing mechanism for indicating the condition of the contours of the cams on cam shafts of engines which latter embody push-rods actuated by the cams and include a distributor shaft rotated in unison with the cam shaft, a rotary disk bearing a cam delineation corresponding to the contour of the cam being tested, a shaft on which said disk is axially mounted, means for detachably connecting said shaft to said distributor shaft to rotate in unison therewith, a stylus arranged to indicate said delineation, a reciprocal shaft on which said stylus is carried, a mounting for said reciprocal shaft, a wire having one end thereof attached to said reciprocal shaft, an expansion spring in said mounting exerting a forward thrust on said shaft and a consequent pull on said wire,

a reciprocal cylinder to which the other end of said Wire is attached, means for clamping said cylinder on the pushrod actuated by the cam being tested, a piston in said cylinder, a stem on said piston adapted to seat on a fixed abutment, an expansion spring in said cylinder bearing on said piston to maintain said stem in its seated position, a flexible tubular shaft encompassing said wire having one end thereof fixed relative to said piston and having its other end fixed to the mounting of said reciprocal shaft.

6. In a cam testing mechanism for indicating the condition of the contours of the cams on cam shafts of engines which latter embody push-rods actuated by the cams and include a distributor shaft rotated in unison with the cam shaft, a rotary disk bearing a cam delineation corresponding to the contour of the cam being tested, a shaft on which said disk is axially mounted, means for detachably connecting said shaft to said distributor shaft to rotate in unison therewith, a stylus arranged to indicate said delineation, a reciprocal shaft on which said stylus is carried, means engageable with the engine push rod actuated by the cam being tested for moving said reciprocal shaft in unison with the engaged push rod; said reciprocal shaft moving means embodying a flexible shaft having a Wire one end of which is connected to said reciprocal shaft and means for connecting the other end of said wire to the push rod,

References Cited in the file of this patent UNITED STATES PATENTS 1,488,968 Wirt Apr. 1, 1924 2,648,912 Osgood Aug. 18, 1953 2,714,328 Hamburger Aug. 2, 1955 2,721,989 Gates Oct. 25, 1955 

